I have tried to find something on this, and I realize that it varies from seller to seller somewhat, but I am a newbie.

If I want to buy something from another user and I feel comfortable with there feedback and so on, then I would send them a pm get their email address they use with paypal and send them money under the purchase of goods? When they receive the confirmed funds they send me the item?

This is assuming that they are taking payment through paypal which I would guess is the easiest/safest way to buy.

Will not having any feedback effect my ability to buy from some sellers?

I always sell to newbies who can show me feedback they have elsewhere like ebay. I then send them a message from ebay and they need to respond through ebay so I know its really them and not just a random user name they picked up.